1. Field of the Invention
The present invention relates to a display device, and more particularly to a technique which is effectively applicable to a random number generating circuit used in a display device.
2. Description of the Related Art
A TFT (thin film transistor)-type liquid crystal display device having a middle-size liquid crystal display panel has been popularly used as a display part of a personal digital assistant, a notebook-type personal computer or the like.
With respect to this middle-size liquid crystal display device, there has been known a liquid crystal display device which is provided with a touch panel arranged adjacent to the liquid crystal display device as an input device for receiving data inputted from the outside. Further, a keyboard has been also used as an external input device conventionally.
Data inputted from such an input device may be provided with coding such as encryption for securing secrecy. Random numbers are generally used for coding and hence, a display device is also required to include a random number generating circuit.
However, a conventional display device is not provided with a random number generating circuit, and attempts have been made to find out an optimum random number generating device for a general-use display device.
On the other hand, conventionally, there have been proposed various random number generating circuits. JP-A-06-051957 discloses a circuit which generates random numbers referred to as M series by a shift register. However, JP-A-06-051957 neither discloses nor suggests a random number generating circuit used by a display device.